Making your own tec pack?

[Billybopsbasher]

Has anyone successfully (or even tried) fitting an aftermarket battery pack to their bike?
Seeing as tec packs are so thin on the ground, how feasible would it be to make your own packs.. Eg there's loads of videos on YouTube with guys getting 36v packs by 10x5 configuration and getting 10.5-11ah like focus themselves.
Is there anything stopping me from purchasing higher capacity cells and potentially getting a 500wh(or even625?) pack on the downtube?
Apologies if this turns out to be a stupid question as I've very limited knowledge on the subject other than the above.
Appreciate any knowledgeable replies?

 

[Zimmerframe]

I don't recall reading about anyone making their own tec pack, but there are a few threads about the trailwatts system and the ebooz system :

Trailwatts Focus TEC battery - EMTB Forums

New Booster Battery system compatible with all major motor brands - EMTB Forums

E Booz battery extender DO NOT BUY - EMTB Forums

 

[stiv674]

I wouldn't think it's as simple as just plugging in another battery, I'd assume it would have to 'talk' to the bike computer etc...

I'm waiting patiently for the Trailwatts battery but not holding my breath if I'm honest

 

[stiv674]

I'd like some clever person to see if the internal battery with, I assume 18650 batteries, can be upgraded to the newer higher capacity 21700 batteries

 

[Billybopsbasher]

That would be even better... Id love for a 625wh pack for the downtube or even a replacement internal pack too for long range bikepacking or big days out in the lakes etc

 

[SEBA]

Sunscribef

 

[Jaanos]

Hey team, so I rigged up my own home made TEC pack for my Focus, its 158 Wh and seems to work perfectly. With the bike switched off you plug the pack in and the bike immediately powers on. This is different to the TEC pack - where you have to use the bikes power switch to turn it on. I'm slightly concerned this may not be good for the bikes electronics so wanted to ask if anyone has the ebooz system if this is the same functionality you experience? Also is there any direction as to what battery you should use first (internal or external)? I have a TEC pack as well but it is more capacity than I normally need so too heavy and mounted high on the frame so I wanted a smaller, lighter option that also leaves the water bottle cage free for a bottle... I can mount this is a small bag under the downtube so the weight is low. Any advice greatly appreciated. Cheers.

 

[maynard]

nice . Tec pack ? Is it for a giant bike?

 

[sdcoffeeroaster]

Hey team, so I rigged up my own home made TEC pack for my Focus, its 158 Wh and seems to work perfectly. With the bike switched off you plug the pack in and the bike immediately powers on. This is different to the TEC pack - where you have to use the bikes power switch to turn it on. I'm slightly concerned this may not be good for the bikes electronics so wanted to ask if anyone has the ebooz system if this is the same functionality you experience? Also is there any direction as to what battery you should use first (internal or external)? I have a TEC pack as well but it is more capacity than I normally need so too heavy and mounted high on the frame so I wanted a smaller, lighter option that also leaves the water bottle cage free for a bottle... I can mount this is a small bag under the downtube so the weight is low. Any advice greatly appreciated. Cheers.

View attachment 36384

View attachment 36385

Wow, very interesting. Where did you get the plug for this? How is it wired up internally. I don't suppose you are using any circuit board with it like the TEC pac. This would be ideal for most of us as long as we're sure it doesn't damage any of the electronics. Nice job!

 

[sdcoffeeroaster]

The Rosenberger connectors are not exactly cheap....$73. and the only place I have found them so far. Might be better to find to broken charger but no luck on that yet either. C003-MA-2000 Rosenberger | Cable Assemblies | DigiKey

 

[Jaanos]

Cheer for the reply, I got the cable from luna cycles, not cheap but better than other outlets.

Hoping to hear what functionality the ebooze system has when used with the focus - from what i can see it only has a level indicator on the pack, no on/off switch etc so thinking it would function the exact same way. I know this pack works and if it was connected the wrong polarity etc it would not work and cause some major issues very quickly. I'm still unsure if I want to run it long term though...

Rosenberger Magnetic Connector Set Male and Female

Providers of quality ebikes, electric bike batteries, motors and components at affordable pricing.

lunacycle.com

Wow, very interesting. Where did you get the plug for this? How is it wired up internally. I don't suppose you are using any circuit board with it like the TEC pac. This would be ideal for most of us as long as we're sure it doesn't damage any of the electronics. Nice job!

 

[Gspot]

Haven't tested the range?
We're did you get your Focus?

 

[sdcoffeeroaster]

Cheer for the reply, I got the cable from luna cycles, not cheap but better than other outlets.

Hoping to hear what functionality the ebooze system has when used with the focus - from what i can see it only has a level indicator on the pack, no on/off switch etc so thinking it would function the exact same way. I know this pack works and if it was connected the wrong polarity etc it would not work and cause some major issues very quickly. I'm still unsure if I want to run it long term though...

Rosenberger Magnetic Connector Set Male and Female

Providers of quality ebikes, electric bike batteries, motors and components at affordable pricing.

lunacycle.com

They are showing the male and female ends. If so I guess you used the male end to make a charger adaptor cable if you are using the std charger. Do they include both for $49.? Looks like they are on back order for now. DId you just leave the data lines open? With a 3D printer you could make a nice water bottle shaped housing for this along with a spot welder and a BMS. If you used the std charger does it shut off normally? Are the data lines necessary to control the charger if so?

BMS probably dictates the size, ie width:
Do you use it before the main battery runs out or after? What does the display register with one of these plugged in? I found a battery like yours here:

36V 4.4Ah 10S2P INR18650P Li-Ion Battery For Balance Scooter Board USA Seller. | eBay

Assembly: 10S2P. Category：Li-ion Battery. Lifecycle of single cell: >85% capacity after 1500 cycles, > 70% capacity after 3000 cycles. Cell: INR18650P-2200. Why choose we battery?. Power: 158W.

www.ebay.com

Sorry for all questions, great job!! So for only about $100. you have an extra 10-12 miles of range, not bad.
Thanks

 

[Jaanos]

They are showing the male and female ends. If so I guess you used the male end to make a charger adaptor cable if you are using the std charger. Do they include both for $49.? Looks like they are on back order for now. DId you just leave the data lines open? With a 3D printer you could make a nice water bottle shaped housing for this along with a spot welder and a BMS. If you used the std charger does it shut off normally? Are the data lines necessary to control the charger if so?

BMS probably dictates the size, ie width:
Do you use it before the main battery runs out or after? What does the display register with one of these plugged in? I found a battery like yours here:

36V 4.4Ah 10S2P INR18650P Li-Ion Battery For Balance Scooter Board USA Seller. | eBay

Assembly: 10S2P. Category：Li-ion Battery. Lifecycle of single cell: >85% capacity after 1500 cycles, > 70% capacity after 3000 cycles. Cell: INR18650P-2200. Why choose we battery?. Power: 158W.

www.ebay.com

Sorry for all questions, great job!! So for only about $100. you have an extra 10-12 miles of range, not bad.
Thanks

Just to make sure we are clear on this, I am not endorsing using a system like this. I have used it once and it worked fine, however, with the bike off - plugging in the home made pack switches the bike on instantly. This is different to my actual TEC pack from focus where you have to turn the bike on normally with the power button. For this reason I am hesitant to use the pack as i am not sure it is bypassing the internal battery as it would with the focus TEC pack. This should only be a problem if you use the internal battery first then plug the home made version in and potentially drain the internal battery further than it should. Having said that, with the home made version plugged in the bike shuts off after about 400m of vert which is about what you would expect from a half size pack. Then when powering on with the internal battery the indicator is at 100%. So I am 99% sure it works fine.

I just want to know if any ebooze owners can explain how their pack functions when used on a focus. Does it turn the bike on instantly like I have explained or is there some intelligence built into the pack that enables the power switch on the bike to be used. If this is the case and the ebooze system functions the same then I would be happy using this pack.

Regarding the charger, I bought a cheap charger specific to the battery I purchased and wired up the female connector to it. You get both from luna cycle for 50 bucks.

Cheers.

 

[sdcoffeeroaster]

Did the smaller pac register any bars on the display?

Yes there could be issues we don't know about and would void the warranty as well if your bike is under one.

I don't see why the regular charger would not work. It's a 36v pack and the BMS is what controls the balancing and stops charging the battery to protect it. I'm just not sure of those data wires, lol.

 

[sdcoffeeroaster]

I could not find anything on the ebooze battery. Is that a European company? Thanks

 

[Gspot]

https://www.e-booz.com/prodotto/e-booz-battery-range-extender-da-36v-7ah-250wh/

 

[sdcoffeeroaster]

https://www.e-booz.com/prodotto/e-booz-battery-range-extender-da-36v-7ah-250wh/

Thanks, I don't see a focus cable option although they do say a Rosenberger is available.

 

[Gspot]

Cavo maschio Rosemberger RoPd magnetico per bici Focus e Specialized ~

Cavo maschio Rosemberger RoPd magnetico per bici Focus e Specialized ~

Cavo specifico per connettere l'e-Booz ber250 e l'e-Booz ber370 alla presa originale delle biciclette Focus e Specialized. Lato borraccia con connettore Xt90 lato bicicletta Rosenberger Ropd magnetico.

www.e-booz.com

 

[sdcoffeeroaster]

Thanks, I don't see a focus cable option although they do say a Rosenberger is available.

Cheer for the reply, I got the cable from luna cycles, not cheap but better than other outlets.

Hoping to hear what functionality the ebooze system has when used with the focus - from what i can see it only has a level indicator on the pack, no on/off switch etc so thinking it would function the exact same way. I know this pack works and if it was connected the wrong polarity etc it would not work and cause some major issues very quickly. I'm still unsure if I want to run it long term though...

Rosenberger Magnetic Connector Set Male and Female

Providers of quality ebikes, electric bike batteries, motors and components at affordable pricing.

lunacycle.com

It seems your Aux pack behaves like a charger is plugged into the bike in that the bikes power button turns blue. Does the steps display come on? Does it show several or all the bars for the battery? The charger doesn't cause the steps display to come on. Maybe the Steps computer is expecting a 378 wH battery and anything other than that will not work correctly. All this information is proprietary so we may never be able to feel this sort of home made battery is completely safe. It could affect the battery with continual use. I wish Focus would make smaller bottle size batteries as a lighter and less expensive option. Since they have the TEC pack a 10 or 20 battery (126wH, 252 wH) water bottle pack should be easy for them to make. I did write them a suggestion but they probably don't pay much attention to the US anymore since they pulled out a few years ago....our loss.

 

[Jaanos]

It seems your Aux pack behaves like a charger is plugged into the bike in that the bikes power button turns blue. Does the steps display come on? Does it show several or all the bars for the battery? The charger doesn't cause the steps display to come on. Maybe the Steps computer is expecting a 378 wH battery and anything other than that will not work correctly. All this information is proprietary so we may never be able to feel this sort of home made battery is completely safe. It could affect the battery with continual use. I wish Focus would make smaller bottle size batteries as a lighter and less expensive option. Since they have the TEC pack a 10 or 20 battery (126wH, 252 wH) water bottle pack should be easy for them to make. I did write them a suggestion but they probably don't pay much attention to the US anymore since they pulled out a few years ago....our loss.

Not sure it behaves like a charger as I'm almost certain the main battery isnt connected when the aux pack is connected. I say this as the bike cuts out after around 400m of vert and when removing the aux pack and turning the bike back on, the internal battery has full charge and gets te same range as if I was starting it fresh. If the two packs were connected then it would be in parallel and the 378wh and 158wh would combine and the bike wouldn't cut out until both packs were at low voltage. This could cause a problem for the lower capacity pack as it would deplete faster and potentially go to an unstable low voltage.

On returning home I checked voltage of the aux and it was 33.7v so well and truly depleted. You can measure the volts of the main pack with a multimeter on the charge port once the bike is turned on. I will measure this prior to riding, connect the aux pack and wait for it to deplete ten check the frame pack voltage again to make sure it hasn't been depleted. If this is the case I can't see any reason it would cause a problem using this simple pack.

Anyone with an ebooze system that can comment on its functionality would be greatly appreciated. Cheers.

 

[sdcoffeeroaster]

Not sure it behaves like a charger as I'm almost certain the main battery isnt connected when the aux pack is connected. I say this as the bike cuts out after around 400m of vert and when removing the aux pack and turning the bike back on, the internal battery has full charge and gets te same range as if I was starting it fresh. If the two packs were connected then it would be in parallel and the 378wh and 158wh would combine and the bike wouldn't cut out until both packs were at low voltage. This could cause a problem for the lower capacity pack as it would deplete faster and potentially go to an unstable low voltage.

On returning home I checked voltage of the aux and it was 33.7v so well and truly depleted. You can measure the volts of the main pack with a multimeter on the charge port once the bike is turned on. I will measure this prior to riding, connect the aux pack and wait for it to deplete ten check the frame pack voltage again to make sure it hasn't been depleted. If this is the case I can't see any reason it would cause a problem using this simple pack.

Anyone with an ebooze system that can comment on its functionality would be greatly appreciated. Cheers.

I agree they are both not connected to each other but that instant on is the main issue and difference from the TEC pack.

You didn't say but what does the Shimano display do? Does it come on and register 2-3 bars? Too bad the aspect ratios of that battery pack are not "nicer" but for the price of about $50. I can't complain, lol.

I wrote to "Trailwatts" who makes bottle size batteries for Levos, 252 wH and 504 wH sizes. They were going to look into doing one for the Focus and were seeking a Tec pack "loan" last year to do some reverse engineering. But they got pretty busy and put that project off.

 

[sdcoffeeroaster]

Cavo maschio Rosemberger RoPd magnetico per bici Focus e Specialized ~

Cavo maschio Rosemberger RoPd magnetico per bici Focus e Specialized ~

Cavo specifico per connettere l'e-Booz ber250 e l'e-Booz ber370 alla presa originale delle biciclette Focus e Specialized. Lato borraccia con connettore Xt90 lato bicicletta Rosenberger Ropd magnetico.

www.e-booz.com

I see that it says "exhausted" after the translation so that must mean out of stock like the one here in the US at Luna Cycles. I gave Luna my email address to notify me when they are back in stock.

 

[MartinW148]

I'd like some clever person to see if the internal battery with, I assume 18650 batteries, can be upgraded to the newer higher capacity 21700 batteries

The 21700 cells are physically bigger, so I would guess that's a no.

 

[sdcoffeeroaster]

The 21700 cells are physically bigger, so I would guess that's a no.

That's probably right Martin. The battery is a pretty tight fit right now with barely enough room for cables.

 

[sdcoffeeroaster]

Cheer for the reply, I got the cable from luna cycles, not cheap but better than other outlets.

Hoping to hear what functionality the ebooze system has when used with the focus - from what i can see it only has a level indicator on the pack, no on/off switch etc so thinking it would function the exact same way. I know this pack works and if it was connected the wrong polarity etc it would not work and cause some major issues very quickly. I'm still unsure if I want to run it long term though...

Rosenberger Magnetic Connector Set Male and Female

Providers of quality ebikes, electric bike batteries, motors and components at affordable pricing.

lunacycle.com

Do you think this charger would work once I get the correct connector for it? Luna cycle is also out of chargers too. Item # CHR-42V2A-LI-3PS

LiFePO4 and Li-ion Battery Chargers - ElectricScooterParts.com

LiFePO4 and Li-ion electric scooter and bicycle battery chargers. We carry LiFePO4 battery chargers for electric scooters and electric bicycles.

electricscooterparts.com

thanks.

 

[Jaanos]

Do you think this charger would work once I get the correct connector for it? Luna cycle is also out of chargers too. Item # CHR-42V2A-LI-3PS

LiFePO4 and Li-ion Battery Chargers - ElectricScooterParts.com

LiFePO4 and Li-ion electric scooter and bicycle battery chargers. We carry LiFePO4 battery chargers for electric scooters and electric bicycles.

electricscooterparts.com

thanks.

There is no reason the stock charger wouldn't work as it's the same voltage pack but I haven't tried as has differentconnectors. Charger is a Male connector and so is the home made pack. I bought one on ebay so I could plug both batteries in and charge at the same time.

Cheers.

 

[sdcoffeeroaster]

There is no reason the stock charger wouldn't work as it's the same voltage pack but I haven't tried as has differentconnectors. Charger is a Male connector and so is the home made pack. I bought one on ebay so I could plug both batteries in and charge at the same time.

Cheers.

I think the stock charger might charge too fast though. That small pack says 2 amp max and my charger is 4.5 amps.

You didn't say, but did the display come on and register any bars with the smaller pack?

 

[Jaanos]

I think the stock charger might charge too fast though. That small pack says 2 amp max and my charger is 4.5 amps.

You didn't say, but did the display come on and register any bars with the smaller pack?

That's definitely a consideration. Depends what c rating your pack has but slower charging is always a safer bet and better for the battery in the long term.

The display comes on and registers full bars. Not sure how many or if it had dropped any bars before cutting out, definitely wasnt in the red though which is weird. I'll probably test it again soon and will report back. Be great of someone with an ebooze pack could report on functionality. I pmd someone on here that created a thread about theirs but they haven't responded.

 

[sdcoffeeroaster]

That's definitely a consideration. Depends what c rating your pack has but slower charging is always a safer bet and better for the battery in the long term.

The display comes on and registers full bars. Not sure how many or if it had dropped any bars before cutting out, definitely wasnt in the red though which is weird. I'll probably test it again soon and will report back. Be great of someone with an ebooze pack could report on functionality. I pmd someone on here that created a thread about theirs but they haven't responded.

I bet the bars just reflect the voltage, 5 bars being a full charge.

I just realized that the TEC pack has an on/off switch. If it didn't, then the TEC pack would instantly start the bike just like you experienced with your DIY pack. Based on this I think your pack, without an on/off switch is behaving normally. I have ordered a battery and charge but the Rosenberger connector is in short supply. I did find the one end at nextwarehouse.com for $16. plus $11. shipping but since it's a special order it is going to take many weeks to get it. I plan to do a housing in Solidworks and make a 3D printed version once I receive the battery but the Rosenberger connector will have to wait I guess. Maybe I'll add an on/off switch as well.

I also saw that there are 10p1s packs (10 batteries) for about the same price that come with a charger. This is only about 108 wH but might fit in a water bottle size and only weigh about a lb. but maybe only 8 miles range so maybe that size would not be worth the effort.